A natural object usually has smooth edges, hence, a natural image taken by a camera should keep such a characteristic. However, as various nonlinear transform methods (such as threshold value judgment, gamma correction, color transform, histogram equalization, and bilateral filtering, etc.) are often used in image signal processing, such transform methods will result in aliasing noises at image edges due to a nonlinear characteristic of itself, while well performing noise lowering or enhancement, thereby affecting evaluation of the image by the people.
In order to obtain an image of smooth edges, aliasing noises resulted from nonlinear transform need to be alleviated or eliminated, so as to recover anti-aliasing edges of a natural object. However, the inventors found that in the relevant art, there exists no processing method for a nonlinearly filtered image, and there exist no method and apparatus for recovering anti-aliasing edges, hence, in some scenarios, a nonlinearly filtered image has no natural edge.
It should be noted that the above description of the background art is merely provided for clear and complete explanation of the present application and for easy understanding by those skilled in the art. And it should not be understood that the above technical solution is known to those skilled in the art as it is described in the background art of the present application.